1. Field of the Invention
The present invention is directed to a semi-frozen liquid beverage dispensing machine and a method of controlling semi-frozen liquid beverage in a dispensing machine.
2. Prior Art
Various known types of beverage devices dispense semi-frozen and chilled liquid beverages. The chilled beverages may take various names such as “sicilian granita” or “slushies”. The consistency of the beverage product is a thick slush that stands up in a cup or container. The beverage dispensing device itself typically includes a cylinder within a transparent bowl that visually displays the product wherein the cylinder is refrigerated with refrigerants. In one arrangement, a hollow stainless steel cylinder is arranged horizontally in the bowl. A helical blade driven by an electric motor continually moves across the external portion of the cylinder to scrape off or “harvest” frozen crystals formed by the refrigeration process. Accordingly, over time, the entire contents of the bowl become semi-frozen and the product is mixed while in the bowl.
The solids content (sometimes described as “brix”) and consistency of the semi-frozen product should be maintained. If the product is too warm, it turns liquid. If the beverage is cooled too much, the beverage thickness becomes excessive.
Controls have been placed on the refrigerating system in a number of ways. In one arrangement, the compressor will switch off in response to achieving a set temperature. In another arrangement, torque systems measure viscosity of the product through resistance on a dasher or drive motor. The resistance is measured either mechanically or electronically and the measurement is constant whether the compressor is running or not. This type of measurement is somewhat inefficient and causes short cycling of the compressor. While measuring torque in this manner, it can be measuring frost build-up on the evaporator and not the viscosity of the mass in the bowl causing false consistency results and short cycling the compressor.
It is known that when product is placed in the bowl in the liquid state, it will initially be brought down in temperature until it reaches the freeze-down stage. Thereafter, it has been observed that the product begins to thin down. For example, a product that has excellent thickness immediately following an initial freeze-down could be runny several hours later even if the temperature is held constant. This may be due to many factors which include the growth of ice crystals on the evaporator over tire. As water is extracted from the solution to maintain ice crystal growth, more of the syrup components are freed and act as lubricants which stimulate growth of the ice crystals. This effect, combined with a greater disparity between the size of the solid ice crystals and the remaining liquid components results in the thinning down of the product. Accordingly, it has been found that the use of temperature only as a control is unsatisfactory.
In existing torque control systems, a gear motor places an auger drive axle several inches away and radially offset from an electric motor. The motor dangles below the motor drive axle and is allowed several inches of radial arch motion. When the motor is off, when there is no resistance on the auger, the motor hangs directly below the auger drive axle, tripping a limit switch that is mounted to the right of the motor.
The control circuit for the bowl refrigeration is run through the limit switch, causing refrigeration suddenly to open (and the compressor to start) if the motor is dead hanging. When the auger encounters resistance, the electric motor actually rotates radially in a clockwise motion through an arc (defined by the length of offset between the auger drive axle and the motor). This clockwise rotation causes contact with the limit switch to be broken, shutting off refrigeration for the bowl.
It is desirable to provide a system to control product density rather than a system to simply control the temperature in the bowl.
It is desirable to provide a system to control product density rather than a system to monitor and control frost build-up on the evaporator.
The liquid to replenish the bowl must be refilled from time to time. In a typical dispenser, the top of the bowl is removed and liquid is replenished by an attendant. To refill, the liquid mixture is poured from a bulk storage container into the open top by an attendant.
The liquid may be packaged for storage and transportation in various ways. In one type of bulk packaging, a flexible inner storage membrane, such as plastic, is retained within a rigid package such as a cardboard or corrugated box. Various delivery systems are known, for example, those contained in the Applicant's pending U.S. patent application Ser. Nos. 09/650,586 and 09/814,081, each of which is incorporated herein by reference.
There remains a need to provide an integrated beverage dispenser and a storage and delivery mechanism for bulk packaging.
It is also desirable to increase production capacity of a semi-frozen liquid beverage dispenser beyond the capacity of the particular bowl and automatically fill the bowl from bulk storage.
It is also desirable to replenish liquid in the bowl by automatically refilling the liquid dispenser device.
Existing bowl designs for dispensing apparatus will occasionally have a tendency to have inefficient fluid dynamics and consequently develop dead spots wherein icebergs may form thereby causing an unsightly and unappetizing appearance. One solution in the past has been to add additional mechanical mixing sources to minimize this effect.
It would be desirable to provide a novel type of bowl design having a geometric shape which would create sufficient fluid dynamics to eliminate the foregoing inefficiencies and maintain a more consistent semi-frozen beverage product.
In existing designs it is difficult to evacuate all liquid from the bowl thus causing a mess when removing the bowl for cleaning. Some systems employ devices to adjust the bowl at such times.
It would be desirable to have a bowl design that efficiently evacuates the liquid without any manipulation of the bowl.
In existing designs ambient air is allowed to come in contact with the product with all its possible air born contaminates.
It would be desirable to have a system that filtered the air that came in contact with the product.
Existing systems rely on the operator to manually adjust the machine for variables such as consistency and brix for each flavor type.
It would be desirable to have a system that identified the product and automatically adjusted torque and mix ratios.
In existing systems the operator has to manipulate a gasket and place same on the machine to create a seal between the bowl and the machine.
It would be desirable to have a gasket system that attaches easily to the bowl before affixing it to the machine.